This invention relates generally to a device for securing and positioning a workpiece during a machining process and more particularly to a gearless indexing device to simplify the accurate drilling of holes, and cutting of gear blanks, fluted reamers, and other components.
In the drilling of a component, or in the drilling, milling, grinding or cutting of the teeth on gear blanks, the flutes on reamer blanks and similar mechanical components, it is first necessary to accurately position and secure the workpiece to be machined in a suitable rotatable chuck, faceplate or like type holder. It is then further necessary to provide some suitable means for positioning and repositioning the workpiece by incremental steps so the required holes, gear teeth, flutes or the like can be cut into the workpiece by some suitable drilling, milling, grinding or cutting attachment which can be used for this purpose. The accurate positioning and repositioning of the workpiece for these processes is attained by serially or incrementally moving or rotating the workpiece a predetermined arcuate or angular distance from an initial zero position until the workpiece moves or rotates back to the zero position.
Dividing or indexing mechanisms for use in conjunction with lathes for milling and grinding gear blanks, fluted reamers, and similar mechanical components are known in the prior art. These for the most part are devices having a holder for the workpiece which coacts with mechanical gearing. Such prior art devices while accurate within their limitations as to size and number of indexing arrangements, are also expensive, and therefore are not readily available to small machine shops, hobby centers, or hobbyists who need to perform this type of machining operation.
Other less expensive forms of devices are also known but these present problems respecting their operation and reduction in accuracy as they wear.
Thus, for example, U.S. Pat. No. 1,200,638 illustrates a device which does not utilize mechanical gears. In U.S. Pat. No. 1,200,638 the workpiece, a gear blank, is shown as disposed in a holder which is also the dividing or indexing plate. In the repositioning of the gear blank after each tooth is cut, the holder must be rotated to permit a removable and replaceable pin to be aligned with the next incremental hole in the holder or indexing plate, to enable an associated turn buckle element to be so adjusted that the workpiece i.e. The gear blank will be rotated the required incremental arcuate or angular distance for cutting the next gear tooth. This device and its operation is not only limited in accuracy but is tedious and time consuming during the use thereof in order to achieve the desired movement within the capability of the device.
Although machine shops, big and small, have successfully employed devices similar to the above described device shown and disclosed in U.S. Pat. No. 1,200,638, the limitations inherent in such devices and the need for more accurate and simpler means for accomplishing the desired dividing and indexing for the drilling, milling, grinding or cutting of gears, reamers, and other mechanical components will be readily apparent to those skilled in the art.
The present invention seeks to meet this problem of the prior art by providing a dividing or indexing device which also eliminates mechanical gears and other complex combination of elements and seeks to meet the problems of the prior art by providing a relatively simple fitting and arrangement which is easy to manipulate and operate in the drilling, milling, grinding and cutting of gears, reamers, and the like mechanical component blanks.
In the present invention, the holder for the mechanical component, blank or workpiece to be machined is separated from the actuating means which coacts with and moves the holder and the workpiece mounted therein the desired incremental arcuate or angular steps required for a particular drilling, milling, grinding or cutting pattern or program by placing the holder on one end of a rotatable actuating shaft and operatively and selectively connecting an actuating means to the actuating shaft at a point spaced from the holder for the workpiece as is shown in the illustrated embodiments of the invention herein. The actuating means is operative to establish by suitable measuring means the required incremental distance for any given pattern or program and further includes associated elements which both transfer this measured distance and rotate the shaft in arcuate or angular increments equivalent to this measured distance so that the shaft, holder and the workpiece are simultaneously rotated to permit the desired drilling, milling, grinding or cutting operation to be performed on the workpiece.